An LCD includes an upper substrate and a lower substrate. Opposite inner sides of the substrates are provided with a transparent electrode, and the electrode is coated with a layer of alignment film (PI) for aligning an initial position of a liquid crystal; and opposite outer sides of the substrates are provided with a polarizer. A layer of liquid crystal molecules is sandwiched between the two substrates. The LCD changes the polarization state of light by controlling the orientation of the liquid crystal molecules under an electric field, and achieves the penetrating and stopping of the optical path via the polarizer. Thus, the LCD can display the images.
Pat. Pub. No. CN101191935A, published on Apr. 6, 2008, discloses a substrate for an LCD panel, an LCD panel, and an LCD device. The substrate includes a display area, an edge area, and a sealant adhering area. The sealant adhering area is arranged between the display area and the edge area; a layer of alignment film is coated in the display area and the edge area, and the edge area is provided with a pattern area without being coated with the alignment film.
FIG. 1 shows another conventional LCD panel: the opposite inner sides of the two substrates are respectively coated with a layer of alignment film (PI), which is used to align the liquid crystal molecules, and a liquid crystal material is filled in the space formed by the two substrates and a sealant. A certain distance must be reserved between a periphery of the sealant and an edge of the panel, to ensure that the panel can be cut from a large master plate.
The alignment film (PI) generally is not overlapped with the sealant. However, with the development of a narrow frame technology, a part of LCDs begin to use a method that the alignment film (PI) is partially overlapped with the sealant, as shown in FIG. 2. The alignment film (PI) is made of a water absorbing material, if the alignment film (PI) is completely overlapped with the sealant, and the alignment film (PI) is in contact with the outside air, the alignment film (PI) will be hydrolyzed because of absorbing the outside vapor, and the reaction will spread into the panel; thus, the alignment of the liquid crystal molecules in the panel is affected, to cause the nonuniform display of the part near the frame, thereby generating serious murs.